The choice of cathode for a battery is significant in terms of the desired performance and cost. The cathode composition is an important factor for the energy density that can be achieved. For lithium-ion batteries, the choice of cathode can also involve a balance between power available and energy utilization. Thus, the choice of cathode is important for the planned mode of application of the battery.
Useful candidates for cathode materials for lithium-ion batteries include lithium iron oxides, lithium iron phosphates, and lithium iron silicates.
A drawback in the field of lithium-ion batteries is the difficulty of synthesizing cathode material at moderate temperatures. Use of moderate temperatures is desirable for efficiency, but has been a drawback because it limits the choice of cathode material that can be synthesized.
It is also desirable to provide cathode materials with a high degree of compositional homogeneity and control, as well as uniformity and purity. Conventional methods may require temperatures as high as 1000° C.
Another problem is to provide cathode material having long term stability under various battery operating conditions.
A further drawback is that the properties desired for the battery, such as energy density, lifecycle, and stability can require cathode materials of high compositional uniformity.
These requirements can place a high value and strict conditions on processes for synthesizing cathode materials.
In addition to bulk materials for cathodes, various architectures for making a lithium ion battery may require thin film cathodes. For example, a cathode can be formed as a thin film in a pattern to be interspersed or interleaved with electrolyte and anode components. The cathode itself can be composed of multiple thin film layers. The difficulties with these approaches include controlling the uniformity, purity and homogeneity of the cathode layers, as well as controlling cathode surface and edge quality.
Difficulties in the production of thin film cathodes include limited ability to deposit uniform layers of cathode material with sufficient speed and throughput for commercial processes.
There has long been a continuing need for processes for synthesizing cathode materials for lithium ion batteries at moderate temperatures to provide materials having a high degree of compositional homogeneity, uniformity and purity.
There is also a need for processes for making cathode materials that provide control over the composition and stoichiometry of the materials.
What is needed are soluble precursor compounds and compositions for processes for synthesizing cathode materials for lithium ion batteries.